The vocabulary of endearment, complaint, and abuse, provides, I think, almost the only specimens of words that are purely emotional, words from which all imaginative or conceptual content has vanished, so that they have no function at all but to express or stimulate emotion, or both. And an examination of them soon convinces us that in them we see language at its least linguistic. We have come to the frontier between language and inarticulate vocal sounds.
—C. S. Lewis, British writer, Studies In Words, 1960